About Time

If you’ll excuse the expression, we have a long history with time. For most of us, this history is somewhere between “who cares” and “possibly interesting”.

When did it become important enough for people to try and figure out how long a day was? What about a month? A year?

Why are there 24 hours in a day? Why are there 60 minutes in an hour, and 60 seconds in a minute?

There has long been an “intertwining” between time and religion. And between time and agriculture. What about time and the movement and position of celestial bodies? As the seasons change, we stop seeing some stars and start seeing others. Don’t forget time and tides…

Speaking of tides, what about time and navigation? At some point people realized we had an equator, and that what we saw in the night sky depended on our latitude, and when we saw it depended on our longitude. There is more information about this in our article about Time and Navigation.

Knowing the correct time can, literally, be a life-saver. There are several places on various coasts that look the same. Heading towards one of these places will be safe, while heading toward another similar looking place cause cause your ship to founder on rocks. Back in the day, when your ship was finishing its ocean voyage and you could see the landmark, without knowing the correct time you can’t tell your longitude. So you have a choice to make.

Time was of lifesaving importance for trains as well. There were often stretches of single track between places with bi-directional traffic. It was critical that the engineer, conductor, and switch yard folks knew and agreed on the time to make sure that trains were where they were supposed to be, when they were supposed to be there1.

Knowing the time isn’t important, until it is…

Let’s take an example from the financial markets. Say, for example, trading opens at 9:00 and closes at 4:00. Back in the day, this all happened on the trading floor and anybody who wanted to trade did their work on the floor, or had phone lines open between them and a trader. Time passed and technology advanced, and now most trades are handled electronically. Would you be surprised to know that a large percentage of trades in the USA are High-Frequency Trades, where often enough a position is held for a fraction of a second? To make this happen, the decisions must be scheduled and made pretty quickly, and the faster this can be done the more successfully it can be done. We’re talking about executing between one and twenty-nine thousand (or more) trades a second!

Knowing the time to better than a thousandth of a second isn’t important, until it is…

Tragedies happen. If, for example, a building catches fire or a plane crashes, trained investigators can usually “put the pieces back together” to find out what happened. Depending on the circumstances, this knowledge can be used to make safer buildings or planes — to save lives. These situations are relatively easy to understand because the components “fit together” and that knowledge can help develop the sequence of events. But we live in an increasingly inter-dependent world. Do you remember the power blackout that hit eastern Canada and the northeast United States in 2003? For several hours’ time before the blackout, information was coming in from various locations that was pointing at problems. The rate at which these reports increased until, in the final 9 seconds before the blackout, about 10,000 separate incidents were recorded. The bad news is that since these incidents happened over a wide area and they were not accurately time-stamped, there was no way to correctly order and therefore understand the chain of events. All of the “post-mortem” reports on the event listed accurate time-stamping of data as one of the essential and critical needs of the new systems. Unfortunately, while this better time-stamping will be of great value in understanding how the next major blackout happens, it will still take another catastrophic blackout to understand where the current weaknesses are.

Knowing the correct time isn’t always important. But sometimes it is, and too often we don’t realize this until after the fact.